Duo-switch gate circuit operable with positive or negative pulses



p 1961 J. E. BIGELOW DUOSWITCH GATE CIRCUIT OPERABLE WITH POSITIVE OR NEGATIVE PULSES Filed May 27, 195'? 2 K35 51 PS5 wztw A INVENTORt JOHN E, BIGELOW ATTORNEY United States Patent The present invention relates in general to electronics and has more particular reference to an improved electronic switching circuit forming an electron gate especially well suited for use in conjunction with a scaler or rate meter for impulse counting purposes, although capable of employment wherever use of the gating circuit may be found desirable.

An important object of the present invention resides in providing a gating circuit embodying an electron flow valve normally operable to transmit a signal, when the control element or grid of the valve is at a selected datum potential value and otherwise to block transmission of the signal; a further object being to provide control means for preventing transmission of the controlled signal through the valve or gate whenever the controlling potential upon the grid of the valve increases or decreases above or below the datum value; a still further object being to provide an electronic gate operable to transmit a signal wave to be controlled so long as the control element or grid of the gate valve is maintained at a datum potential level, such as zero potential with respect to ground, and for blocking operation of the gate valve in the event that and Whenever the potential on the control element becomes either positive or negative with respect to ground potential.

Another important object is to provide a gating circuit embodying a gate valve and means to disable the valve for signal translation therethrough in response either to a positive signal potential of selected value or to a signal of negative character and selected value.

Briefly stated, in accordance with a preferred aspect of the invention, the signal to be controlled may be applied to the cathode of a signal controlling three-element electron flow device, the device being conductive to pass the signal therethrough When its grid is at zero potential with respect to ground. When a gating or control signal of negative character is applied to the control grid of said device, it Will be cut off, and hence will become non-conducting. Signal pulses are also prevented from being transfererd through the electron flow device in response to the application upon the gating circuit of controlling signals of positive character, such signals being applied to the control grid of an auxiliary threeelement electron flow device, causing the same to become heavily conductive, said auxiliary device being electrically interconnected with the signal controlling flow device in manner causing the same to become cut off and hence non-conductive, in response to heavy current flow in the auxiliary flow device. The signal controlling and auxiliary electron flow devices may, if desired, each comprise one half of a double electron tube.

The foregoing and numerous other important objects, advantages and inherent functions of the invention will become apparent as the same is more fully understood from the following description, which, taken in connection with the accompanying drawing, discloses a preferred embodiment of the invention.

Referring to the drawing:

The single figure of the drawing is a diagram of circuit components and connections forming a gate circuit embodying the present invention.

To illustrate the invention, the drawing shows a principal electron flow device 9 having an anode 10, a cathode 11 and a control grid 12. The gating system also embodies an auxiliary electron flow device 9 having an anode 10, a cathode 11 and'a control grid 12'.

- The anodes of the devices 9 and 9 may be electrically interconnected through a 4-70 kilohm resistor 13,, the anode of the valve 9 being electrically connected with a suitable source \14 of B+ potential through the resistor 13 and a kilohm resistance element 15 interconnected in series to form a voltage divider, the anode of the device 9' being connected with the potential source 14 through the resistance element 15. The anode of the valve 9 may also be connected to ground through a 220 kilohrn resistor 16, and with a signal output line 17 through a 500 mmf. condenser 18.

The cathodes of the flow devices 9 and 9' may be interconnected through a 15 kilohrn resistor 19 in series with an 82 kilohm resistor 20, the cathode of the flow device 9 being connected to ground through the resistor 19 and a 10 kilohm resistance element 21, the cathode of the device 9 being connected to ground through the resistance elements 20 and 21.

The control grid of the flow device 9 may be connected with a line 22 through which control signals of negative character may be applied thereto.

The control grid of the flow device 9' may be connected as through a 1 megohm resistor 23 to a line 24 through which control signals of positive character may be applied thereto, said control grid being also connected with the anode of said device 9', as through an 0.002 mfd. condenser 25.

The signal to be controlled may comprise a wave train embodying the unfiltered cycle pulsations produced by full Wave rectification of conventional 60'cycle electrical energy fluctuations. Such a signal may be supplied to the cathode of the valve 9" through a signal input line 26 containing a 330 kilohm resistor 27, and transferred thence through the flow device 9 to the output line 17 when the flow device is 'in conducting condition, as when the control grid 12 thereof is at a selected datum poten tial, such as 'zero potential with respect to ground.

"Two separate kinds of gate controlling signals of opposite character may function independently to close the gate and block transmission of the controlled signal through the valve 9 to the output line 17. When a gating signal of negative character is applied through the line 22 upon the grid 12, the valve 9 will become out cit and non-conducting whereby transmission of the controlled signal will be blocked. To insure sharp cutoif of the tube 9, an appropriately low plate voltage may be applied on its anode 10 from the source 14 through the voltage divider comprising the resistors 13, 15 and 16. The other gate controlling signal serves to prevent pulses from passing the device 9 whenever such other controlling signal becomes positive. This other eontrolling signal is delivered through the line 24, through the resistor 23, to the grid of the flow device 9. Application of a positive signal potential upon the grid 12' renders the flow device 9 strongly conductive, thereby increasing plate current flow through the resistor 15., such action reducing the potential at the plate of the valve 9. Such increase in current flow through the valve 9 also serves to increase the voltage at the cathode of the valve 9 as the result of the increase in current flow through the cathode of the valve 9'. The alteration of potential on the anode and cathode of the valve 9 thus: accomplished by increase in current flow through the valve 9, causes the valve 9 to become non-conductive and hence blocks the transfer of the controlled signal therethrough to the line 17.

The capacitor 25, which is connected between the grid and plate of the valve 9', prevents the potential at the anode of the valve 9 from becoming positive too rapidly when the signal applied through the line 24 returns to a zero voltage value, thereby preventing stray pulsations from being produced in the output line 17.v

The output line 17, of course, may be connected with counting circuits or other operable means which it may be desired to operate in response to the transmission of the controlled signal through the valve 9.

It is though that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous change may be made in the form, construction and arrangement of the several parts without departing from the spirit and scope of the invention, or sacrificing any of its attendant advantages, the form herein disclosed being a preferred embodiment for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

1. An electronic switching device for providing &- on control of the passage of a pulse train therethrough comprising: first and second electronic switches, each having input, output, and control electrodes; means for applying said pulse train to the input electrode of said first switch; biasingmeans for biasing said first and second switches to render said first switch normally conducting and said second switch normally nonconducting; first means for applying a pulse of a given polarity to said control electrode of said first switch to render said first switch non-conducting; second means for applying a pulse of polarity opposite to said given polarity to said control electrode of said second switch to render said second switch conducting; the time and frequency of application of said pulses of opposite polarities to their respective control electrodes, being independent of each other; means comprising a resistive element in series with said output electrodes of said first and second switches, for reducing the potential at said output electrode of said first switch with respect to a reference level when said second switch is conducting and means comprising a resistive element in series with said input electrodes of said first and second switches for increasing the potential at said input electrode of said first switch with respect to said reference level when said second switch is conducting; whereby said first switch will be cutofi by the application of a pulse of said given polarity to the control electrode of said first switch, or by the application of a pulse of polarity opposite to said given polarity to the control electrode of said second switch, or by both.

2. An electronic switching device .for providing oilon control of the passage of a pulse train therethrough comprising: first and second electronic tubes, each having a cathode, anode, and control grid; means for applying said pulse train to the cathode of said first tube; biasing means for biasing said first and second tubes to render said first tube normally conducting and said second tube normally non-conductingfirst means for applying a neg ative pulse to said control grid of said first tube, to render said first tube non-conducting; second means for applying a positive pulse to said control grid of said second tube to render said second tube conducting; the time and frequency of application of said positive and negative pulses to their respective control grids, being independent of each other; means comprising a resistive element in series with said anodes of said first and sec ond tubes, for reducing the potential at said anode of said first tube with respect to a reference level when said second tube is conducting; and means comprising a resistive element in series with said cathodes of said first and second tubes for increasing the potential at said cathode of said first tube with respect to said reference level when said second tube is conducting; whereby said first tube will be cut-off by the application of a negativepulse to the control grid of said first tube, or by the application of a positive pulse to the control grid of said second tube, or by both.

References Cited in the file of this patent UNITED STATES PATENTS 2,405,237 Ruhlig Aug. 6, 1946 2,435,207 Dimond Feb. 3, 1948 2,448,336 Weiner Aug. 31, 1948 2,538,500 Bess Jan. 16, 1951 2,557,644 Forbes June 19, 1951 2,591,088 Millrnan Apr. 1, 1952 2,632,845 Goldberg Mar. 24, 1953 2,757,282 Exner July 31, 1956 2,797,265 Stuart-Williams June 25, 1957 2,943,260 Barnard June 28,- 1960 

